U.S. patent application number 13/374129 was filed with the patent office on 2012-04-19 for solid state thermoelectric power converter.
Invention is credited to Gerald Phillip Hirsch, Jon Murray Schroeder.
Application Number | 20120090534 13/374129 |
Document ID | / |
Family ID | 45476812 |
Filed Date | 2012-04-19 |
United States Patent
Application |
20120090534 |
Kind Code |
A1 |
Schroeder; Jon Murray ; et
al. |
April 19, 2012 |
Solid state thermoelectric power converter
Abstract
High efficiency conversion of heat energy to electrical energy
is achieved using a ring of metallic components and anodically
sliced, reduced barriers, high purity n-type and p-type
semiconductor wafers. Energy produced by heating one set of fins
and cooling another set is extracted from a ring of bismuth
telluride based n-type wafers and antimony telluride based p-type
wafers using make-before-break control of MOSfet switch banks.
Standard AC frequencies and DC output result from rectification of
make-before-break high frequency switched very high currents in the
ring and a DC to AC converter. Solar energy stored in porcelain
fragments extends the time that solar energy can be used as the
heat source for the thermoelectric generator device.
Inventors: |
Schroeder; Jon Murray;
(US) ; Hirsch; Gerald Phillip; (US) |
Family ID: |
45476812 |
Appl. No.: |
13/374129 |
Filed: |
December 13, 2011 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
11259922 |
Oct 28, 2005 |
8101846 |
|
|
13374129 |
|
|
|
|
10154757 |
May 23, 2002 |
|
|
|
11259922 |
|
|
|
|
Current U.S.
Class: |
117/81 |
Current CPC
Class: |
H01L 35/30 20130101 |
Class at
Publication: |
117/81 |
International
Class: |
C30B 11/02 20060101
C30B011/02 |
Claims
1-50. (canceled)
51. A method for making reduced barriers n-type semiconductor
material casting of: (a) high purity elemental selenium material in
an amount of from five percent (5%) to twelve percent (12%) by
weight; (b) high purity elemental bismuth material in an amount of
forty percent (40%) to sixty percent (60%) by weight; and (c) a
remaining weight percentage being of high purity elemental
tellurium material, the method comprising the steps of: (a) mixing:
i. high purity elemental selenium material; ii. high purity
elemental bismuth material; and iii. high purity elemental
tellurium material, wherein the elemental material weights are
respectively within the preceding percentages; (b) heating said
mixture to a temperature of at least eight-hundred degrees
centigrade (800.degree. C.) whereby said mixture melts; (c)
preparing a mold for receiving said melted mixture by compressing
in a holding framework around an elongated rectangularly-shaped
pilot boule replica that has been inserted at a center of said
holding framework to a depth of eighty percent (80%) of the length
of the boule replica a mixture of: i. fly ash beads that float on
water; and ii. five percent (5%) to twenty percent (20%) of
low-dropping point kiln grease; (d) inserting a single crystal seed
at the top of said mold adjacent to a corner of said pilot boule
replica with a narrow reduced barriers face of said single crystal
seed touching the the pilot boule replica; (e) carefully removing
said pilot boule replica from said mold by gentle shaking and
twisting and slow extraction of said pilot boule replica; (f)
pouring said melted mixture into said mold; (g) allowing said
mixture to cool; and (h) removing said reduced barrier n-type
semiconductor material casting together with the attached reduced
barriers seed from said mold.
52. A method for making reduced barriers p-type semiconductor
material casting of: (a) high purity elemental bismuth material in
an amount of eight percent (8%) to twelve percent (12%) by weight;
(b) high purity elemental antimony material in an amount of eight
percent (28%) to thirty-two percent (32%) by weight; and (c) the
remaining weight percentage being of high purity elemental
tellurium material, the method comprising the steps of: (a) mixing:
i. high purity elemental antimony; material ii. high purity
elemental bismuth material; and iii. high purity elemental
tellurium material, wherein the elemental material weights are
respectively within the preceding percentages; (b) heating said
mixture to a temperature of at least eight-hundred degrees
centigrade (800.degree. C.) whereby said mixture melts; (c)
preparing a mold for receiving said melted mixture by compressing
in a holding framework around an elongated rectangularly-shaped
pilot boule replica that has been inserted at a center of said
holding framework to a depth of eighty percent (80%) of the length
of the boule replica a mixture of: i. fly ash beads that float on
water; and ii. five percent (5%) to twenty percent (20%) of
low-dropping point kiln grease; (d) inserting a single crystal seed
at the top of said mold adjacent to a corner of said pilot boule
replica with a narrow reduced barriers face of said single crystal
seed touching the pilot boule replica; (e) carefully removing said
pilot boule replica from said mold by gentle shaking and twisting
and slow extraction of said pilot boule replica; (f) pouring said
melted mixture into said mold; (g) allowing said mixture to cool;
and (h) removing said reduced barrier n-type semiconductor material
casting together with the attached reduced barriers seed from said
mold.
52-56. (canceled)
Description
RELATED APPLICATIONS
[0001] This application is a division of U.S. patent application
Ser. No. 11/259,922 that is a continuation-in-part of pending U.S.
patent application Ser. No. 10/154,757, filed May 23, 2002,
entitled "Torus Semiconductor Thermoelectric Device" published Nov.
27, 2003.
TECHNICAL FIELD
[0002] This invention relates to a circular array of semiconductor
and conductive elements that comprise a high efficiency
thermoelectric generator device. Energy generated by a temperature
differential between hot and cold fins of the thermoelectric
generator device is more efficiently converted to electrical energy
by a combination of both high efficiency semiconductor elements and
a high frequency direct current to direct current switching
component. When combined with an H-bridge the combination produces
alternating current output of various standard voltages and
frequencies. Improved cooling efficiency is obtained by increasing
the surface area of the cold fins. This is accomplished by
splitting and displacing the lower portion of the cold fin. This
improved efficiency device is especially suitable for conversion of
solar energy to electricity by the use of a porcelain based heat
storage system.
BACKGROUND ART
[0003] Thermoelectric generator devices have been used for many
years for specific applications where the simplicity of design
warrants their use despite low energy conversion efficiency.
[0004] The voltage produced by a thermoelectric generator device
depends on the Seebeck voltage of the dissimilar metals used.
Seebeck voltages are higher for some semiconductor materials
especially n-type and p-type elements made primarily of mixtures of
bismuth, tellurium, selenium and antimony.
[0005] To compete with more traditional forms of heat to
electricity conversion thermoelectric generator devices must be as
efficient as possible. A preferred means to achieve such high
efficiency is to arrange the thermoelectric generator elements in a
circle with only a very small region used to extract the energy
produced by the thermoelectric generator elements.
[0006] Patent PCT/US97/07922 to Schroeder discloses such a circular
arrangement. Art teaching in this case focused on 3 means to
extract energy for the high current in the ring of elements; 1--a
vibrating mechanical switch, 2--a Hall effect generator and 3--a
Colpits oscillator. Coatings of hot and cold elements of the
thermoelectric generator device are claimed for selenium, tellurium
and antimony among others but not for mixtures of these
elements.
[0007] U.S. Pat. No. 6,222,242 to Konishi, et al. discloses
semiconductor material of the formula AB.sub.2, X.sub.4 where A is
one of or a mixture of Pb, Sn, or Ge, B is one of or a mixture of
Bi and Sb and X is one of or a mixture of Te and Se. These
represent Pb, Sn or Ge doped bismuth telluride.
[0008] U.S. Pat. No. 6,274,802 to Fukuda, describes a sintering
method of making semiconductor material whose principle components
include bismuth, tellurium selenium and antimony.
[0009] U.S. Pat. No. 6,340,787 to Simeray discloses a
thermoelectric generator component of bismuth doped with antimony
and bismuth tellurium doped with selenium wherein said components
are arranged into a rod. Very low voltages are converted using a
self-oscillating circuit at the expense of power output.
[0010] U.S. Pat. No. 6,172,427 describes the use of a
thermoelectric generator device on the exhaust portion of a
combustion-based car using an electrically driven wheel wherein
excess heat energy is converted to electric power for the
vehicle.
[0011] Published US application 20040134200 to Schroeder, et al.,
entitled "Torus Semiconductor Thermoelectric Chiller" describes the
combination of a semiconductor thermoelectric generator device and
absorption chiller to produce refrigeration and facilitate the
collection of water from air.
[0012] Published U.S. patent application 2003/0217766 to Schroeder,
et al. entitled "Torus Semiconductor Thermoelectric Device"
describes a circular array of semiconductor elements utilizing
individual casting of wafer components.
[0013] Wire saws have been used in the semiconductor industry for
some time. U.S. Pat. No. 6,283,111 to Kazunori Onizaki, et al.,
uses a wire saw to cut single silicon crystals and cutting is done
by pressing the ingots against the wire. U.S. Pat. No. 6,802,928 to
Akira Nakashima utilizes a jig to improve cutting of silicon wafers
and cuts by pressing the ingot against the wires.
[0014] U.S. Pat. No. 6,617,504 to Takeshi Kajihara, et al., uses a
mixture of bismuth telluride and antimony telluride as a
semiconductor but doped the mixture with a dopant of p-type or
dopant of n-type. The mixtures are made into small globules for
particular applications.
[0015] U.S. Pat. No. 6,313,392 to Yasunori Sato, et al., teaches
the use of Bi.sub.1.5 Sb.sub.0.5 Te.sub.3 to prepare p-type
semiconductors for hot pressing and cold pressing.
[0016] U.S. Pat. No. 6,274,802 to Katsushi Fukuda, et al., uses the
composition Bi.sub.0.4 Sb.sub.1.6 Te.sub.3 for p-type semiconductor
manufacture.
[0017] U.S. Pat. No. 4,855,810 to Allan Gelb, et al., teaches the
use of a p-type semiconductor comprising 75 mole percent antimony
telluride, 25 mole percent bismuth telluride with 3 percent excess
tellurium, and 0.1 percent lead.
SUMMARY OF THE INVENTION
[0018] It is a purpose if this invention to provide high conversion
efficiency of heat energy to electrical energy by making use of
anodically sliced, reduced barriers, n-doped and p-doped
semiconductors attached to metal heat-conducting elements in a
circular arrangement of thermoelectric generator components.
[0019] It is a further purpose of this invention to operate
thermoelectric generator devices in high current low resistance
mode by increasing electrical conduction in n-doped and p-doped
semiconductors using reduced barriers processing.
[0020] It is a further purpose of this invention to provide a high
efficiency of transmission of energy contained in a thermoelectric
torus by an improved make-before-break switching control system
utilizing special physical connections to the ring-shaped
thermoelectric generator device.
[0021] Another purpose of this invention is to provide for the use
and storage of solar energy. Excess electrical output energy is
stored using resistance heating into a heat store allowing
temperatures in the store to be greater than the highest
temperature that can be handled by the thermoelectric generator
device.
[0022] It is a further purpose of this invention to provide a novel
method of slicing selenium-bismuth-telluride-based and
antimony-bismuth-telluride-based semiconductor wafers from boule
castings.
[0023] It is a further purpose of this invention to provide a novel
composition of bismuth doped diantimonytritelluride suitable for
use as a p-type semiconductor element.
[0024] It is a further purpose of this invention to provide a means
to energize the control board and thereby replace the need for a
battery in the device.
[0025] It is a further purpose of this invention to improve the
efficiency of power conversion by splitting the ends of cold fins
and thereby increasing the surface area available for cooling.
BRIEF DESCRIPTION OF DRAWINGS
[0026] FIG. 1 illustrates a boule casting of reduced barriers
semiconductor.
[0027] FIG. 2 illustrates a damage-free electrical wire-sawing
fixture that cuts by anodic corrosion.
[0028] FIG. 3 is an exploded view illustrating various elements
that are unified in assembling a standard coupon.
[0029] FIG. 4 illustrates an assembled standard coupon.
[0030] FIG. 5 illustrates a cold fin modified for improved
cooling.
[0031] FIG. 6 illustrates a standard coupon with a special cold fin
and attached upconverter power takeoffs.
[0032] FIG. 7 illustrates how a standard coupon is connected to a
modified cold fin with upconverter power takeoffs.
[0033] FIG. 8 illustrates how a modified additional cold fin with
upconverter power takeoff connects with insulation and a standard
coupon using a special cold fin having upconverter takeoffs.
[0034] FIG. 9 illustrates an assembled ring with upconverter power
takeoff.
[0035] FIG. 10 illustrates a bonded ring with upconverter power
takeoff, secondary coils and switch banks.
[0036] FIG. 11 illustrates the assembled ring with completed
upconverter and connecting cables.
[0037] FIG. 12 illustrates a cross section of fuel-fired
thermoelectric generator device with atmospheric exhaust.
[0038] FIG. 13 illustrates a cross section of a thermoelectric
generator device configured for the utilization of hot circulating
air.
[0039] FIG. 14 illustrates a self-starting circuit that allows
electrical elements to derive power for operation as the
thermoelectric ring is initially heated.
[0040] FIGS. 15a, b and c illustrate a preferred system for solar
energy collection
[0041] FIG. 16 illustrates heat energy store and a preferred system
for solar energy collection, storage and re-utilization.
[0042] FIG. 17 illustrates the use of a high efficiency
thermoelectric generator device to power an electric motor that
connects to the drive shaft of an automobile.
[0043] FIG. 18 illustrates the use of heat stored in ceramic
fragments to drive a conveyance using a thermoelectric generator
wherein wheel braking energy is conserved using resistance heating
in the heat store.
[0044] FIG. 19 illustrates a hybrid vehicle having both a heat
reservoir source and dedicated thermoelectric generator device and
in addition a second thermoelectric generator device that burns
liquid fuel.
[0045] FIG. 20 illustrates an assembly of multiple thermoelectric
generator devices such as those depicted in FIGS. 12 and 13
organized for synchronous controlled output.
[0046] FIG. 21 illustrates a method to synchronize multiple
thermoelectric generator devices.
[0047] FIG. 22a illustrates a non-combustible plug containing
igniter means and 22b illustrates a non-combustible plug containing
a temperature sensor.
[0048] FIG. 23 illustrates the improved energy output of square
waves derived from the H-bridge compared to a sine wave output of
other systems.
[0049] FIG. 24 illustrates the nature of the output waveforms
controlling the ring current showing a make-before-break format
accomplished by inverting the electric output waveform wherein
voltage spikes are removed.
[0050] FIG. 25 illustrates a printed circuit controller board with
designated functions.
[0051] FIG. 26 illustrates a thermoelectric generator device
modified to operate with liquid or gaseous fuels and hot air from
solar heating that can also be operated as a solid state
chiller.
DISCLOSURE OF THE INVENTION
[0052] To illustrate this invention figures are drawn to show
components of some implementations of the invention. It should be
understood that these figures do not in any way limit this
invention as describe in the claims.
[0053] The invention comprises a heat source, a plurality of
thermoelectric coupons arranged in a ring, a means for extracting
electrical energy from said ring. Energy is produced in the form of
very high currents circling through a plurality of coupons. These
currents are induced when metallic hot and cold fins of the
thermoelectric coupons are respectfully heated and cooled. The term
coupon is used herein to identify the combination of a hot fin, a
high purity n-type semiconductor, a cold fin, a high purity p-type
semiconductor and a metal wedge. Multiple coupons are assembled to
make a ring. The ring conformation is important in reducing losses
that would otherwise occur if a resistive conductor like copper
were used to electrically connect ends of a linear array of
coupons.
[0054] The heat source can be any of a myriad of combustible
materials such as gases of hydrogen, methane, ethane, propane,
butane, liquids such as gasoline, kerosene or crude oil, and solids
such as wood, used tires, straw and other celluloid materials and
coal. In addition the heat needed for electricity production can
come from concentrated sunlight. A preferred heat source is heat
energy stored from collected solar radiation. Waste heat from these
and other combustion activities can also be stored and used as
needed.
[0055] For several means used to generate heat, the hot gasses are
passed over the hot fins to heat them. In a preferred embodiment
gas or liquid is combusted directly under the hot fins. In a
preferred configuration the hot fins project inward with regard to
a circle or torus of coupons and the hot air is passed through or
combustion occurs adjacent to the hot fins.
[0056] In another preferred embodiment the rate of fuel combustion
is controlled to match the electrical demand of the thermoelectric
device. In the case of gas or liquid being combusted near the hot
fins, infrared radiation which passes through or is given off from
the hot fins is radiated back on the hot fins by a reflective
metallic dome.
[0057] In another preferred embodiment a temperature sensor on a
cold fin is used to sense temperature above 100 degrees C. and
cause an open circuit in a fail-closed valve supplying fuel to the
thermoelectric generator device in the event of a cooling blower
failure or low cooling air velocity across cold fins.
[0058] In another preferred embodiment a temperature sensor on a
cold fin is used to sense temperature above 100 degrees C. and
cause an open circuit in a blower motor supplying hot air to the
thermoelectric generator device in the event of a cooling blower
failure or low cooling velocity across cold fins.
[0059] In another preferred embodiment a reflective dome has
backing of an insulating layer. An opening is made in the top dome
to allow hot air to escape or a tube is attached to direct the
escaping air.
[0060] A unique method is used to extract energy from the high
current flowing in the thermoelectric ring without interrupting
current flow or the direction of current. An integrated metallic
takeoff apparatus is inserted between any two coupons. In a
preferred embodiment the takeoff apparatus is made of two takeoffs
each having two connections to metal laminates that form
connections to two sets of MOSfet switch banks. The first takeoff
is made of a special straight cold fin that has been
high-temperature-brazed to 2 sets of multiple thin insulated
metallic strips each sets of strips forming a laminate. One of the
laminates is twisted 180 degrees relative to the other. Both
laminates extend out from the ring and are wrapped in circular
fashion about secondary coils and an E-core. To accommodate the
MOSfet switch banks the end of the takeoffs are folded in the
direction away from the ring. These folded sections of the straight
and twisted laminates are individually soldered to one of two banks
of MOSfet switches. On the opposite side of the MOSfet switch banks
are soldered a second complementary set of laminates formed in a
manner to extend back to the ring forming a closed current loop.
The preferred connection from the complementary laminates utilizes
a high temperature soldered modified cold fin. This modified fin is
soldered to a coupon from which the original cold fin was removed.
As with the takeoffs from said straight cold fin said modified cold
fin connects to two sets of multiple thin insulated metallic strips
forming a laminate. One of the two laminates is twisted 180 degrees
relative to the other. The first set of laminates attached to the
straight cold fin and the second set of laminates attached to the
modified cold fin are arranged to complement one another in such a
manner that when connected to the MOSfet switch banks the 180
degree twisted takeoffs form one closed loop and the straight
takeoffs form another.
[0061] In a preferred embodiment a shortened cold fin is placed 180
degrees from the additional cold fin to maintain physical symmetry.
In this case the upconverter connects to the ring through only cold
fins thereby reducing the amount of heat entering the upconverter.
Insulating material is placed between the two cold fins of the
power takeoff as well as strips forming the laminate and the
current loops that conduct current around the upconverter. This
insulating material is preferably a thin layer of mica. In addition
the insulating material can be a thin layer of room-temperature
vulcanizing rubber coated with zirconium or other ceramic beads.
Other kinds of insulating non-ceramic beads of same particle size
can also be used.
[0062] This upconverter assembly provides two current loops in
opposite directions around secondary coils and a high frequency
E-core. The current flow is determined by the condition of each
switch bank.
[0063] The power takeoff upconverter is controlled by a circuit
board with a pulse width modulator chip driving multiple inverted
MOSfet drivers. The inverted MOSfet drivers create a
make-before-break mode for current direction through power takeoff
loops. Without inversion sharp spikes are produce during the
reversal in the secondary because current is interrupted in the
ring. By inverting the drives, current in the ring continues to
flow and no electromagnetic pulses occur. The number of switch
chips employed in parallel is determined by the maximum amount of
current generated in the ring and depends on the capacity of the
MOSfet switches. For example in a 5-kW thermoelectric generator
device ten MOSfet switches in each switch bank safely commutate
about 2000 amps.
[0064] In addition to the secondary coils that output power from
the ring four additional secondary windings supply isolated power
for components of a controller circuit board.
[0065] In a preferred embodiment power to the controller circuit
board at startup is provided by a special component, eliminating
the need for a battery to do this task. This component is powered
with current from the ring such that when the ring reaches 0.6
volts it provides 12 volt, 100 milliamps output to operate the
controller circuit board. The component connects to each side of
one of the upconverter switch banks. The output current to the
special component declines when MOSfet switch banks become active
and voltage drops to zero. A diode bridge of the component prevents
power from entering the special component after the controller
board becomes powered by secondary power from the E-core
upconverter.
[0066] A pulse-width modulator chip is used to control the MOSfet
switches. If a simple oscillating circuit is used optimum power is
not obtained. If the drive of the pulse-width modulator is not
overlapping very high spikes of current are induced in the primary
and secondary windings of the upconverter. Such spikes would
adversely affect electric devices that use the secondary voltage
outputs.
[0067] Secondary windings in the E-core of the upconverter
transformer produce AC output voltages at higher frequency than
useful. The number of windings needed depend on the voltage driving
the ring and the coupling efficiency of extracting that energy.
This number of windings can be determined by those skilled in the
electronic arts. For example a ring with 60 coupons can produce 3
volts in the primary to drive 2000 amps and using a 1:40 winding
ratio a secondary voltage of approximately 120 volts AC is
obtained.
[0068] Achieving the proper alternating current energy out of a
circle of thermoelectric coupons requires additional special
conversion components. Important components involved in the
extraction of electrical energy are rectifier bridges to convert
high frequency switching DC output into DC and an H-bridge that
converts rectified secondary voltage to the proper 50/60 Hertz
alternating current. The waveform produced from the H-bridge is
controlled by inputs from a pulse-width modulator.
[0069] This thermoelectric generator device is very quiet when
running thus providing an opportunity to replace noisy gasoline
driven implements and appliances.
[0070] To provide these benefits details are given for making and
using a simple circular collection of coupons. Each coupon is made
by alternating a cold fin, that is, a metal fin to be cooled, a
reduced barriers n-type semiconductor, then a hot fin, that is
heated, then a p-type reduced barriers semiconductor followed by a
metallic wedge component. The wedge allows for the hot fins and
cold fins to be rectangular and still be formed into a ring. The
wedge also protects the p-type semiconductor in assembly after
soldering of the coupons. Use of the wedge allows coupon
connections to all be metal to metal in the assembly of the ring.
An alternative procedure is to make cold fins tapered or hot fins
tapered or both cold and hot fins tapered in the region of contact
with the semiconductor wafers.
[0071] For clarity of the disclosure and definition of the claims
the following terms are defined:
[0072] "Semiconductor" means: a mixture of one or more elements
that has the property of allowing either electrons or holes to move
through the mixture depending on whether the mixture has an excess
n-type or p-type doping. The semiconductor nature of thermoelectric
wafers is well established in the electronic literature.
[0073] "Fin" means: an elongated metal slab optionally straight,
tapered, or split on one end, the other end being soldered to an
n-type semiconductor and on the other side to a p-type
semiconductor and on either side soldered to a conductive
wedge.
[0074] "Cold fin" means: a fin to be cooled.
[0075] "Hot fin" means: a fin to be heated.
[0076] "Coupon" means: a repeating component of the thermoelectric
generator device made up of at least one n-type semiconductor, one
hot fin, one p-type semiconductor, and one cold fin. In the device
having a wedge component with each set of fins and semiconductors a
coupon includes the wedge component. A coupon that does not use a
wedge component has the hot fin, the cold fin or both tapered in
the region that is adjacent to the n-type or p-type
semiconductor.
[0077] "Kester's solder" means: Lead-free solder paste consisting
of 96.5% tin and 3.5% silver.
[0078] "Wafer" means: an n-type or p-type semiconductor made in the
shape of thin slab where the thickness of the shortest dimension is
from 5% to 20% of the either of the other dimensions. An example is
a 40 mil thick piece of semiconductor material 0.75 inches by 0.75
inches that is used to create the Seebeck voltage of the
coupons.
[0079] "Wafer side" means: the surface area denoted by the larger
dimension of a wafer where when placed in the coupon the wafer side
becomes the current carrying side.
[0080] "Wafer edge" means: the surface area denoted by the smallest
dimension of a wafer. Before a wafer is placed in the coupon the
wafer edges are coated with insulator to reduce current
leakage.
[0081] "Upconverter" means: a high frequency transformer controlled
by MOSfet switch banks having two single turn loops, one of which
has current flowing opposite to the other, an E-core to facilitate
high frequency transformer efficiency and multiple secondary
windings having a number of turns corresponding to the designed
output voltages.
[0082] "High purity" means: purity of 99.9% or greater for the
components to be combined.
[0083] "Boule" means: a mass of semiconductor that is caused to
grow with reduced barriers during casting.
[0084] "Reduced barriers" means: a semiconductor product showing
the property of a single face after a sharp break of a
semiconductor wafer and characteristic low resistance in the boule
of semiconductor material. In the boule form a Seebeck voltage is
greater than 50 millivolts at a 200-degree centigrade temperature
differential. Another property of a reduced barriers boule is
calculated resistance equal to or less than 0.000006 Ohms
determined by measuring voltage along 2 inches of the boule when a
1 amp current is passed along the long axis of the boule.
[0085] "Phosphorous nickel" means: An electroless plating product
that contains from 1% to 10% of phosphorous combined with
nickel.
[0086] "Distinct orifice" means: an opening in an enclosure that
allows air, gaseous fuel or atomized fuel to pass, exhaust to exit
and recycled air or fluid to exit the device. It can be just an
opening in a flat or rounded structure or it may be a duct attached
to said flat or rounded structure.
[0087] "Alternate fin" definition: a fin to be cooled is the
alternate of a fin to be heated and conversely.
[0088] "Alternate semiconductor" definition: p-type and n-type
semiconductors are alternates of one another in coupon
assembly.
[0089] "Box" definition: The term "box" is used herein to denote an
enclosure that can be used to maintain components of the invention
in a fixed physical relationship. While a box is not necessary for
the invention to be practiced it is a practical feature of the
invention. As an example in a preferred embodiment the "box" is
made of two serving pans commonly used in a buffet with one
inverted over the other.
[0090] "Anodic slicing" means: A process of cutting semiconductor
matter using only electrolytic dissolution to remove that portion
of the matter required to produce a slice of the bulk matter.
[0091] Before describing how to produce components of the
invention, figures are provided to illustrate a working version.
Examples are intended to illustrate the basic principles and
elements of the device. Examples are given for a variety of
applications but by no means represent the broad applications of
this invention.
[0092] FIG. 1 illustrates reduced barriers casting set 1 and the
product 2, a boule made by this novel crystal growing procedure.
The procedure applies to n-type and p-type doped
selenium-bismuth-telluride-based and
antimony-bismuth-telluride-based semiconductor materials. The
growth of reduced barriers semiconductor is achieved by using a
crucible 3 to pour combined melted high purity elements 4 into a
rectangular mold 5. The mold is prepared by compressing an inert
casting matrix 7 around the replica 6, a pilot, of the boule to be
cast. The casting matrix 7 is made by adding 5% to 20% by weight of
low-dropping-point kiln grease to small, spherical, hollow fly ash
ceramic beads that float on water. After compressing the casting
matrix in a holding framework 8 a reduced barriers seed crystal 9
having dimensions in the range of 0.5-2 mm by 4-10 mm by 10-20 mm
is inserted at the top of the holding framework 8 adjacent to the
pilot 6. The thin face of the seed crystal is placed adjacent to
the pilot in a corner. The pilot is then lightly shaken and twisted
and then vertically extracted without disturbing the mold. The
surface of the reduced barriers seed crystal 9 shows a single face
and serves as the nucleation site for reduced barriers growth of
the boule product. Melted semiconductor material 4 is then poured
into the mold and allowed to slow-cool for 15 minutes. The cooling
rate of the material is about one-hundred degrees (100.degree.) per
minute. This cooling rate results in reduced barriers growth from
top corner of the mold to the bottom. The seed crystal 9 remains
attached to the boule product 2 as expected for growth of a reduced
barriers from seed. The reduced barriers nature of the boule
product 2 is indicated by the absence of grain boundaries on the
surfaces of the boule product 2 after it is removed from the mold
5.
[0093] The reduced barriers nature of the boule product 2 is
further supported by the electrical characteristics of the boule 2
that are determined by hot point probe measurements on the surface
to determine Seebeck voltage and semiconductor-type. Seebeck
voltage is characteristically between 52-72 millivolts at a
200-degree centigrade temperature differential. The reduced
barriers nature of the semiconductor is further supported by the
resistance of final shaped crystal boule product 2 and is
determined by measuring the voltage across a 2-inch separation
along the boule product 2 when 1 amp DC is passed along the axis of
the boule 2. The resistance calculated from voltage measurement
across a 2 inch separation on the boule product 2 is less than
0.0003 Ohms. The resistance of each 40-mil wafer is calculated with
the above data to be less than 0.000006 Ohms per wafer.
[0094] Production of uniform wafers is obtained using a wafer
cutting assembly 10 shown in FIG. 2. The boule product 2 or a
portion of it is mounted to a motor-driven slide 11 with a tilt of
the upper portion toward cathode cutting wires 12. Cutting wires 12
form a single continuous line. Cutting wires 12 are separated by
about 45 mils and held in alignment by threads of carriage bolts
13. The cutting wires 12 are made of brass of about 10 mils
diameter. In a preferred embodiment 50-60 portions of wires make up
a cutting head 14. The cutting wires 12 are connected to the
cathode of a power supply 15 and the anode is connected to the
bottom of the boule product. When the power supply is turned on it
produces anodic corrosion as the boule moves slowly through the
cutting wires 12 while 3-5 amps traverse through the boule product
2 to the cutting wires 12. The boule product 2 is moved by force
from a motor 16 drawing a pull wire 17 from capstan 18 between
guides 19. The boule product 2 and cutting wires 12 set are
immersed in deionized water contained in vessel 20 during the
anodic corrosion process. Cutting speed is about 1 hour for a boule
product 2 having a 3/4 inch cross-section. Evolution of gas bubbles
aids in removing dissolved material from the boule product.
[0095] FIG. 3 illustrates a cold fin 21, a hot fin 29, an n-type
crystalline semiconductor wafer 28 and a p-type crystalline
semiconductor wafer 30 together with a wedge 31 that combine to
form a standard coupon 34. FIG. 3 illustrates an exploded view of
the elements of the standard coupon 34 and the relative position
those elements occupy when they are assembled as a complete
standard coupon 34. N-type crystalline semiconductor wafer 28 is
juxtaposed with cold fin 21, which has a layer of solder paste in
the region where the n-type semiconductor wafer 28 bonds to cold
fin 21. Hot fin 29 has layers of solder paste in the regions that
bond to n-type semiconductor wafer 28 and p-type semiconductor
wafer 30. P-type semiconductor wafer 30 bonds with solder paste to
one side of the wedge 31.
[0096] FIG. 4 illustrates the final positions of the elements of
the standard coupon 34 seen in FIGS. 9, 10 and 11. A completed
thermoelectric ring preferably includes sixty-two (62) standard
coupons 34. The number of standard coupons 34 included in a
thermoelectric ring can vary depending on the operating voltage
desired. The Seebeck voltage also effects voltage production for a
given temperature differential between hot fins 29 and cold fins
21. It should be understood that the cold fins 21 need not be
oriented at ninety degrees (90.degree.) to the hot fins 29.
Furthermore it is possible to shape either the hot fins 29 and/or
the cold fins 21 to eliminate the wedge 31.
[0097] Energy conversion in the thermoelectric generator device is
proportional to the temperature difference between adjacent hot
fins and cold fins. As seen in FIG. 5, slitting the bottom and
offsetting three of six sections produces a modified cold fin 21.
Three pin fins 22 are not displace while three pin fins 23 are
displace away from wafer contact surface 24. The wafer contact
surface 24 is undisturbed allowing good contact with the wafers. A
resulting benefit is to increase the surface area for cooling by a
factor of 2. Improved efficiency of cooling is especially important
because the highest reported melting point for
dibismuthtritelluride is 585.degree. C. This temperature is near
the combustion temperature of propane and other common fuels.
[0098] FIG. 6 displays a modified coupon 32 with power takeoffs
using a special cold fin 25 brazed to straight power takeoff 26 and
twisted power takeoff 27. Special fin 25 is soldered to a coupon
from which the original cold fin and its adjacent n-type
semiconductor wafer 28 had been removed. The added cold fin with
takeoffs and adjacent new n-type semiconductor wafer 28 is soldered
to the hot fin 29. Hot fin 29 has next to it a p-type semiconductor
wafer 30 and wedge 31. Power takeoffs 26 and 27 form a
complementary set designed to physically mate to another modified
coupon with takeoffs that match up to the regions of contact to
MOSfet switch banks.
[0099] FIG. 7 shows an additional cold fin 35 with power takeoff
laminates 36 and 37 arranged to be connected to a standard coupon
34. Power takeoff 33 is made up of an additional cold fin 35 to
which is brazed a straight power takeoff laminate 36 together with
a twisted power takeoff laminate 37. The flat additional cold fin
35 allows a tight junction with wedge 31 of standard coupon 34.
During assembly the additional cold fin 35 with attached brazed
laminate straight takeoff 36 and twisted laminated takeoff 37 is
added to the ring adjacent to a standard coupon 34.
[0100] FIG. 8 shows the combined power takeoff 38. It is assembled
by nesting power takeoffs 27 and 37. In the assembled form it can
be seen that the combined takeoffs produce two single turn current
loops one above the other. When current is flowing in the ring and
MOSfet switch banks are closed, current in the loop of the twisted
takeoff 27-37 flows in an opposite direction to that of the
straight power takeoff 26-36. An opening exists at the end of
current loops 27-37 and 26-36 to which the MOSfet switch banks are
solder connected. Assembly is made easier by offsetting the
attachment site of MOSfet switch banks and aligning the attachment
site of the MOSfet switch banks in a direction away from the
thermoelectric ring of standard coupons 34. Insulation 39 is used
to electrically isolate the additional cold fin 35 from modified
coupon 32 shown in FIG. 6. Electrical insulation is also placed
between laminate takeoffs 26-36 and 27-37 as well as between strips
of the laminate. Each strip of the laminate is insulated except at
the ends where they are all brazed in one instance to the cold fin
and in another instance to the MOSfet switch bank. In a preferred
embodiment strips of the laminate are brazed together at the
non-insulated ends prior to being brazed to a cold fin and prior to
being soldered to the MOSfet switch bank. This insulating material
is preferably a thin layer of mica. Alternatively, the insulating
material can be a thin layer of room-temperature vulcanizing rubber
coated with small zirconium or other ceramic beads. Other kinds of
beads of same particle size can also be used.
[0101] An example of a thermoelectric ring 40 prior to soldering is
shown in FIG. 9. It is composed of n-type semiconductor wafers 28,
hot fins 29, p-type semiconductor wafers 30 and wedges 31, and cold
fins 21. The cold fins 21 depicted in FIG. 9 are the un-modified
cold fins depicted in FIGS. 3 and 4. Also shown are the power
takeoffs of the current loops to be connected to switch banks. Also
shown in FIG. 9 are, straight laminates 26 and 36 and the twisted
laminates 27 and 37. In a preferred embodiment to physically
balance the thermoelectric ring assembly, a shortened cold fin 41
is inserted in to the thermoelectric ring 180 degrees across from
the additional cold fin 35.
[0102] FIG. 10 illustrates the bonded thermoelectric ring 42 made
up of thermoelectric ring 40 plus a polyimide insulated metal strap
43 held in compression by 2 diesel spring tensioned clamps 44. Also
shown is a power takeoff upconverter 45 with secondary coils 46,
E-core 47 and MOSfet switch banks 48 and 49. Controller printed
circuit board 50, not shown in FIG. 10, controls MOSfet switch bank
48 solder-attached to straight laminate strap 26 and 36 and MOSfet
switch bank 49 solder-attached to twisted laminate 27 and 37.
[0103] FIG. 11 illustrates how the single turn loops 26-36 and
27-37 are used to switch current direction around the E-core 47
with make-before-break switch banks 48 and 49, and to thereby
convert DC high current in the bonded thermoelectric ring 42 into a
high frequency AC output to leads at 51, 52, 53 and 54. The high
frequency AC is converted back to DC voltage by bridge rectifiers
on controller printed circuit board 50. The output voltage is 40
times higher than voltage produced by the bonded thermoelectric
ring 42 at the switch banks 48 and 49 using upconverter transformer
45 comprising the single turn loops 26-36 and 27-37, a pair of
bi-filar 40-turn secondary coils 46 magnetically coupled through an
E-core 47 and bridge rectifiers on controller board 50. Secondary
power for the printed circuit controller board is delivered by
ribbon cable DIP plug 55. This cable delivers 18 volt AC for 4 or
more independent power supplies each converted to DC using a bridge
rectifier on the controller board 50 of FIG. 12. Power to the
auto-start circuit not shown in FIG. 11 is delivered by a twisted
pair of wires 56 connected across terminals of one of the MOSfet
switch banks 48 or 49. Two ribbon cables shown in FIG. 11 lead from
upconverter 45 to controller board 50 of FIG. 12. One cable
connects switch banks 48-49 to the printed circuit controller board
50 with ribbon cable DIP plug 57. The other ribbon cable delivers
power through DIP plug 55 to a controller board from four, 5 turn
secondary windings contained in secondary winding 46 around the
center stem of E-core 47.
[0104] FIG. 12 illustrates a gas burning thermoelectric generator
device 58 with a case 59, blower 60 and motor 61. The ring 40,
shown in cross-section as a vertical cold fin and horizontal hot
fin, is mounted within the case supported by an insulator 62 below
the cold fins 21. Power takeoff laminates 26-27 conduct current to
the upconverter 45. The control operations are made using the
components of the printed circuit controller board 50. Controller
board 50 drives MOSfet switch banks 48 and 49. Cold air being push
by blower 60 cools the controller board 50, and in addition cold
fins 21 and exits the distinct orifice 63. The blower 60 is sized
and the controller board 50 is arranged with respect to blower 60
so as to allow and least 10% of the air pressure produced by the
blower to impinge on controller board 50. The blower and its motor
are so arranged in said box as to allow said output of the blower
to cool cold fins wherein the amount of air pressure from the
blower is at least 30% of the pressure produced by the blower. Legs
64 below the case 59 hold the case off the ground. Fuel duct 65, a
distinct orifice, and fuel venturi nozzle 66 provide fuel to the
lower combustion bowl 67. Fuel is combusted just below the hot fins
due to stimulated catalytic effect of a burner screen 68.
Preferably the screen is made of perforated ceramic but a metal
screen can be used as well. Efficient ignition of fuel is provided
by non-combustible plug 69 using a resistance-heated igniter 70 or
spark igniter 71. Ignition plug 69 is positioned at the center of
the ring 40 so as to force combustion gas over the hot fins 29.
Combusted gas exits through an exhaust port distinctive orifice 72
in the insulated upper burner bowl 73. Insulation is shaded. This
version of the semiconductor device can also be use to burn liquid
fuels by replacing the venturi gas inlet nozzle 66 with an
atomizing fixture such as a fuel injector. In a preferred
embodiment the insulated upper burner bowl is a double bowl with
insulation in between each bowl.
[0105] In a preferred embodiment non-combustible plug 69 is made of
ceramic material and shaped so as to allow the center portion of
the resistance-heated igniter 70 to occupy the open center of the
ring and side portion to rest upon the end of the hot fins 29
thereby forcing hot air and combusted gases through the hot fins.
Resistance heater 70 can be replaced by a spark igniter 71.
[0106] In another preferred embodiment a temperature sensor is
added to the plug 69. The temperature sensor controls a fuel valve
to cut off fuel in the event that the temperature exceeds a pre-set
value. This value is set below the melting point of the n-type or
p-type semiconductor material.
[0107] In another preferred embodiment cold fins are placed in a
non-metallic U-shaped ring-shaped tray. The tray is filled with
water preferably by an automated filling system with controls to
prevent overflow. The height of the walls of the U-shaped tray and
the width of the tray are adjusted with regard to the air flow of
blower 60 so as to optimize overall cooling efficiency. Electrical
energy production is improved by the evaporative cooling effect on
the cold fins as air from blower 60 passes over water in the
U-shaped tray to exit distinctive orifice 63.
[0108] In another preferred embodiment the U-shaped tray is fitted
on the inside wall with a plurality of spray nozzles facing the
cold fins. Water is pumped from the tray through the nozzles and
the height of the outside wall of the ring is set with respect to
the location of the nozzles so as to have the outside wall catch
excess directed spray. In a preferred embodiment the height of
water in the tray is controlled electronically or by a float
mechanism.
[0109] A versatile configuration of the thermoelectric generator
device 74 is shown in FIG. 13 This version allows the use of
externally supplied hot air. This hot air can be derived from
externally combusted sources, direct solar derived heat or solar
energy stored in hot solids, preferably porcelain fragments. Hot
air from porcelain fragments in heat storage, not shown, enters the
lower combustion bowl 67 through distinct orifice insulated pipe
65. Hot air passes hot fins 29 and exits through insulated upper
bowl 75 then through insulated exhaust pipe distinct orifice 76.
Plug 69 is configured as a temperature sensor with temperature
sensor 77 with sensor output lines 78. The plug forces air around
hot fins 29. Distinct orifice 63 allows cooling air driven by
blower 60 to exit. Features blower 60, motor 61, power takeoff
laminates 26 and 27, upconverter 45, MOSfet switch banks 48 and 49
and controller board 50 are the same as in the fuel burning
versions of the thermoelectric generator device 58 of FIG. 12. This
version is also suitable for utilizing heat from steam sources.
This can be accomplished by providing a heat exchanger between the
source of steam and the re-circulating air line through insulated
pipe 65 of this version of the thermoelectric generator device. As
with the fuel burning version of the thermoelectric generator
device 58 of FIG. 12 this version can also be fitted with a water
filled U-shaped ring under the cold fins to obtain the benefit of
evaporative cooling as air from blower 60 passes over the cold fins
and water in the tray before exiting distinct orifice 63.
[0110] FIG. 14 shows a preferred alternative method to electrically
start the thermoelectric generator device, a special transformer
component 79. When the thermoelectric generator ring 40 is first
heated a small voltage appears across the ring but no current flows
because the MOSfet switch banks are normally open. Low impedance
NPN oscillator circuits 80 can start at 0.6 volts by drawing
current from the ring. This oscillator 80 causes current to flow
alternately in primary windings 81 and 82. The resulting power
output of secondary coil 83 powers the bridge 84 to deliver DC
voltage to low dropout DC regulator 85. Capacitors 86 and 87
condition the output and low drop out voltage DC regulator 85
produces regulated power output of 12 VDC at 100 milliamps from a
set of oscillators 80 connected in series. This component 79
eliminates the need at startup for a special battery to provide
power to the controller board.
[0111] This invention is especially suited to the conversion of
solar energy to electricity. Any of several means to collect solar
energy can be used such as parabolic trough, a solar tracking
funnel, a solar tacking parabolic dish, or a folded lens. A
preferred method is flat 2-axis tracking multi-faceted Fresnel
planar mirror array 88 as in FIGS. 15a, 15b and 15c. The 2-axis
self-tracking feature includes an up/down actuator 89 and motor
driven rubber tires 90. The illustrated version has about 300
mirrors 91. Mirror size is the same as the target 92. Mirrors 91
are individually mounted on an adjustable ball joint not shown to
allow adjustment of each mirror so incoming sun reflects on target.
A trailer ball-hitch 93 shown in FIGS. 15a and 15c allows for
rotation of the mirror array to track the sun during daylight
hours. When the mirror array is moved to the horizontal position a
laser plum-bob is used to shine downward on each mirror 91 so that
each can be aligned to cast the laser beam on to the target 92.
Each mirror is then secured. After all mirrors are aligned the
array is then returned to the solar tracking position. This form of
solar collection allows easy cleaning, alignment and replacement of
mirrors. In severe weather, such as during a hailstorm or high
winds, the array is protected by lowering it to a horizontal
position and the mirrors then covered with plywood storm panels or
other sturdy material.
[0112] The target 92 is a stainless steel spiraled tube with
insulator 94 on the sun side. Hot air passes from a heat store, not
shown, through duct 95 forced by blower, not shown, through
insulated receiver target 92 exiting through insulated line 96
returning then back to the heat storage. The number of mirrors and
the size of the target are adjusted to keep the temperature of the
target below its melting temperature. All transfer tubing and the
blower are heavily insulated to prevent conductive and irradiative
heat loss. The blower is a high temperature resistant type. In a
preferred embodiment the heat store is made up of porcelain
fragments or spheres. The porcelain fragments are contained in 55
gallon stainless steel barrels insulated with one or more low heat
conductive materials such as a ceramic fiber blanket made of
alumina-silia fiber bonded with a resin. This material stands up to
temperatures of 1150 degrees C. Similar insulating material can
also be used. The stainless steel barrels can be replaced by any of
a variety of high temperature air tight metal heat store or any of
a variety of ceramic heat stores.
[0113] FIG. 15b shows a frontal view of the mirror array 91
operating on wheels 90 on a hard surface track 97. FIG. 15c shows a
top view of the mirror array 91 supported by trailer ball-hitch 93
and target 92.
[0114] Another preferred embodiment for solar energy collection and
storage is shown in FIG. 16. An integrated energy system 98
combines a parabolic solar collector 99 on a gun mount, heavily
insulated heat energy store 100, a hot air thermoelectric generator
device 74, electrical energy output unit 101 and a set of batteries
102. Six 12-volt car batteries can supply 3.6-kW for three to five
minutes while the thermoelectric generator device is increasing its
output to assume the load. This feature allows the thermoelectric
generator device 74 to operate at minimum electrical output and
thereby conserve heat. It also reduces the occurrence of light
dimming when high power demand appliances come on-line. As needed
the thermoelectric generator device charges the batteries 102. The
batteries in series are connected through an inverter 103 to the AC
thermoelectric generator bus connecting thermoelectric generator
device 74 to electric energy output unit 101 to match and support
the AC voltage at a predetermined level and assume part of the load
as needed.
[0115] Thermoelectric generator devices can be used in a wide
variety of applications. For example a set of components 104 in
FIG. 17 can be used in an automobile that has a failed engine. An
automobile can be powered using a fuel burning three phase
thermoelectric generator device 58 by removing the old engine and
transmission and adding a single electric motor 105 connected
directly to a special drive shaft 106. FIG. 17 illustrates the use
of a high efficiency thermoelectric generator device to power an
electric motor 105 that connects to the special drive shaft 106 of
an automobile. The speed of the motor resides with a standard foot
pedal 107 that now controls the frequency of the electrical output
of thermoelectric generator device 58. Motor and therefor wheel
direction is controlled by a standard car shifter 108 modified to
cause phase shift for forward, neutral and reverse automobile's
direction.
[0116] Stored heat alone can be use to power a conveyance 109 as
shown in FIG. 18. Heat stored in a porcelain fragment heat store
110 can be transferred to thermoelectric generator device 74 using
a blower 111 then exhaust heat returned to heat store in well
insulated air line 112.
[0117] FIG. 18 illustrates one configuration. A significant feature
of this system is the energy saving in wheel braking. This is done
by shunting the energy in the armature of the electric motor 105 to
resistive heater 113 in the porcelain fragment heat store. A
control box 114 senses over-voltage on the motor power bus
indicating braking with the automobile's hydraulic brake system and
causes the shunting of the excess energy to the resistive heater
element 113. The car then brakes in a forceful and safe manner
controlled by control box 114 and the automobile's normal brake
system. Porcelain fragment heat store 110 can be heated by
circulating heat from a stationary heat store 100 through insulated
input line 115 and returning to stationary heat store 100 of FIG.
16 through insulated output line 116. In addition heat can be
installed in porcelain fragment heat store through resistance
heating from the utility grid through electrical plug 117 and
heating element 118.
[0118] Another preferred conveyance form 119 shown in FIG. 19
comprises hybrid energy sources. For example, a vehicle has both a
porcelain fragment heat store 110 source powering a dedicated
thermoelectric generator device 74 and in addition a second
thermoelectric generator device 58 that burns liquid fuel from the
original fuel tank 120. Hybrid energy source preferred conveyance
form 119 has the same resistance-braking feature as conveyance 109.
Preferred method uses solar heat energy first and supplemental fuel
later. In some cases more energy is needed than the porcelain
fragment heat store 110 can supply and controller unit 121 is
engaged to synchronize the output of both thermoelectric generator
devices 74 and 58. Synchronization is accomplished by the
methodology used for battery backup described in FIG. 16. When
conveyance 119 is operating at maximum power from 74, witnessed by
full extension of the accelerator pedal 107, controller unit 121 is
activated to ignition start thermoelectric generator device 58 that
operates on fuel from the conveyance fuel tank 120. Thermoelectric
generator device 58 comes on line to assume the extra load
increasing output power to the conveyance. For AC drive
applications, phase synchronization between thermoelectric
generator devices 74 and 58 is achieved through controller unit 121
phasing thermoelectric generator device 58 to conform to the exact
phase of thermoelectric generator device 74. When load demands of
the conveyance 119 become low, controller unit 121 commands
thermoelectric generator device 58 to stand at the ready or
thermoelectric generator device 58 can be shut down until later
needed. For high-energy demands multiple thermoelectric generator
devices such as those depicted in FIGS. 12 and 13 can be organized
in an appliance 122 of FIG. 20 comprised of a single rack 123 and
other features.
[0119] A similar dual fuel operation of a vehicle can be
accomplished using the device shown in FIG. 26, organized without
the grid-driven cooling feature.
[0120] A variety of other conveyances can be powered by a single
thermoelectric generator device or a device arrangement in the
nature of that described above. These include but are not limited
to land conveyance such as a bicycle, a truck, a bus, a tractor, a
motor cycle, a snow mobile, flying conveyances such as an air
plane, a helicopter, a gyrocopter, a parasail, and water
conveyances such as a fishing boat ski boat, tug boat, ocean liner,
a jet ski, and submarine.
[0121] FIG. 20 illustrates an appliance 122 included in an assembly
of multiple thermoelectric generator devices 58 organized as an
array of rows and columns that is suitable for synchronous
controlled output. In addition multiple thermoelectric generator
devices 58 can advantageously employ organized combustion venting
fans 124, combined cooling air blower 125 that forces air through
manifold 126. This provides air for cooling the controller board
50, upconverter 45 and cold fins 21. Exhaust air from the cooling
fins that normally exits distinct orifice 63, not shown in FIG. 20,
enters exhaust manifold duct 127 by displacing a moveable cover
making a closed tight air sealing contact between exhaust manifold
duct 127 and exhaust port 72 as shown in FIG. 12 of thermoelectric
generator 58. Air is removed from exit exhaust manifold duct 127
using venting fans 124. Air to cool cold fins is removed from
distinct orifice outlet 63 along with combustion gas from exhaust
port 72 through draft diverter exhaust manifold duct 128 to exhaust
manifold duct 127 diverter by exhaust venting fans 124. When a
thermoelectric generator device 58 is placed in the rack it forces
a closure back to allow continuity between the distribution system
manifolds and the device 58. Thus multiple exterior fans can
provide cooling air for all thermoelectric generator devices 58 in
the single rack 123. In a similar manner combusted air normally
exiting distinct orifice 72 exits through a draft diverter exhaust
manifold 128 connected to high velocity venting fans 124 pulling
air to the outside. Air for combustion is also provided through the
open front of single rack 123. A number of thermoelectric generator
devices can be removed from the single rack for maintenance without
interrupting service from the remaining. FIG. 20 shows a 5 by 5
thermoelectric generator single rack that produces 250-kW when each
thermoelectric generator device 58 produces 10-kW. Four of the rack
systems would produce a Megawatt of energy that will power 1000
average homes or an industrial park. While this FIG. 20 illustrates
the use of multiple combustion thermoelectric generator devices 58,
a similar system using hot air driven thermoelectric generator
devices 74 can also provide similar power output. In this case hot
air is supplied by a manifold to each thermoelectric generator
device 74 and in addition hot air that normally exhausts to the
ambient now enters a tight insulated manifold that eventually
returns to a heat store, a scaled up version of stationary heat
store 100 in FIGS. 16.
[0122] In rack form especially, thermoelectric generator devices
can be synchronized as to phase and voltage output. FIG. 21
illustrates a circuit 129 that shows how a single waveform
generator 130 is used to synchronize all subsequent waveforms by
inserting a wave form from 130 on a pin 203 of pulse-width
modulator chips 131, located on the controller board 50. This
feature causes all thermoelectric generator device outputs to
become synchronous as to phase, waveform and voltage. The power
outputs of each thermoelectric generator device can then be summed
on a common power bus.
[0123] In FIG. 22 another preferred embodiment FIG. 22a shows a
plug 69 with a resistance-heated igniter 70. Plug 69 is placed in
the center of the ring 40. An alternative version of plug 69 has
spark igniter 71 shown in FIG. 22b that can also be used to ignite
gas or aspirated liquid fuel entering the lower combustion bowl.
The plug 69 forces hot gas through the hot fins. When the
thermoelectric generator device utilizes hot air, plug 69 is
equipped with a heat sensor 132 in FIG. 22b to input a thermostat
allowing the system to be under precise control with respect to
heat energy into the thermoelectric generator device and electrical
power out of the thermoelectric generator device. The
thermoelectric generator devices 58 in FIG. 20 each have an
electric ignition starter. In some cases multiple thermoelectric
generator devices will be driven by hot air. In these cases plug 69
has a heat sensor 132 inserted as shown in FIG. 22b. Each of the
displayed non-combustible plugs were shown earlier in less
detail.
[0124] A preferred output means 133 is shown in FIG. 23. A series
of waveforms illustrate the improved energy output of square waves
134 derived from the H-bridge compared to a sine wave 135 output of
other systems. The square wave can output nearly all of the energy
from thermoelectric generator devices 58 and 74 contrasted with the
value of 70% for sine wave outputs. The square wave output does not
adversely affect AC appliances.
[0125] Shown in FIG. 24 is a set of output waveforms 136 from pulse
width modulators 131 used in this invention to control the MOSfet
switch banks. Output non-inverted waveforms 137 show the a and b
outputs of normal waveforms of the pulse width modulator driving
the upconverter 45. The a and b waveforms are electrically combined
and the result is a zero voltage in short intervals shown in 138.
Because no voltage exists no current flows in ring 40. The break in
current in the ring and in the E-core 47 due to short intervals of
no current causes a very large electromagnetic pulse output that
can damage components of the thermoelectric generator device and
can broadcast electromagnetic pulses to damage other appliances.
Waveforms shown in 139 are inverted waveforms caused by using
inverted MOSfet drivers to control MOSfet switch banks 48, 49. When
the inverted waveforms are added in 140 there is no time when a
zero voltage or zero current condition exists in the ring 40 or
E-core 47 as illustrated by summing waveforms in 139. This
comprises a make-before-break switching format accomplished in this
invention.
[0126] Several control features are combined on a single printed
circuit controller board 50 having output grid equivalent
receptacles 141a, 141b, 142 and DC receptacle 143. FIG. 25 shows a
controller board 50 divided into functions; H-bridge 144, a 50-60
Hertz driver 145 for H-bridge 144, a high frequency inverted driver
146 for the MOSfet switch banks 48-49 controlling current flow in
the single turn loops 26-36 and 27-37 of ring 40. Ribbon cable dip
plug 57, not shown, connects between both MOSfet switch banks 48-49
and the dip socket 147 allowing high frequency drive function 146
access to MOSfet switch banks 48 and 49. Current from four
five-turn secondary windings around the E-core 47 connect to dip
socket 148 in power receiving function 149 through a ribbon cable
not shown. Also in power receiver function 149 solder points 150
are provided on the controller board 50 to allow input from the
auto-starter special transformer component 79 contained within the
case 59. Incoming current passing through dip socket 148 powers
isolated, regulated DC power supplies of isolated regulated power
supply function 151. Isolated regulated power supply function 151
consists of 4 isolated, regulated 12 volt power supplies providing
power for the 50-60 Hertz pulse width modulator chip driving
opto-isolator chips, not shown, to drive isolated non-inverted
MOSfet divers in 50/60 Hertz driver function 145 for H-bridge 144.
High frequency pulse width modulator chip in high frequency
inverted driver function 146 drives inverted MOSfet driver chips
also in 146 receiving power from isolated regulated power supply
function 151. Current from the 40-turn secondary bifiler high
frequency output leads 51, 52, 53, 54 connect to bridge rectifiers
152 and 153. One bifiler high frequency output lead set 51-52
attaches to bridge rectifier 152 at pin 154 and 155. The second 40
turn secondary bifiler high frequency output lead set connects to
bridge rectifier 153 at pins 156 and 157. Pins 154, 155 and pins
156, 157 are high frequency AC 25 amp connections. High power
output from the upconverter 45 totals 50 amps DC, and requires that
high currents be transferred onto the printed circuit controller
board 50. This is achieved using a 20 mil patterned copper sheet
158 placed over the corresponding regions on the controller board
50 during manufacture. Bridge rectifiers 152, 153 connect to source
and drains of the MOSfet transistors of the H-bridge 144 using the
patterned copper sheet 158. Also connected to the patterned copper
sheet 158 are the power output connections to grid-equivalent
receptacles 141a, 141b, 142, and DC receptacle 143. Receptacle 141a
delivers 120 volt AC at 50/60 Hertz from one side of the H-bridge
144. Grid equivalent receptacle 141b delivers 120 volt AC at 50/60
Hertz from the other side of the H-bridge 144. Receptacle 142
delivers 240 volts AC at 50/60 Hertz from both sides of the
H-bridge 144. DC receptacle 143 delivers 120/240 volt DC by
connections to bridge rectifiers 152 and 153 through patterned
copper sheet 158. DC receptacle 143 delivers 120 volt and 240 volt
DC power from the thermoelectric generator device. Power from DC
receptacle 143 can be regulated internal to the thermoelectric
generator device or externally by any of the following topologies;
buck, boost, buck-boost, sepic, fly back, forward, 2-switch
forward, active clamp forward, half bridge, push pull, full bridge,
phase shift ZVT, low drop out voltage regulator, and others. Also
connecting to the patterned copper sheet are electrical connections
not shown that powers the internal blower motor 61 in
thermoelectric generator devices 58, 74, and dual use
thermoelectric hybrid 159. Blower motor 61 operates with AC or DC
voltages as required. In a preferred embodiment the grid equivalent
receptacles 141a, 141b, 142, 143 are mounted on the case 59. In
many applications utilizing a dedicated thermoelectric generator
device the DC and AC outputs are connected directly to
corresponding DC and AC motors.
[0127] FIG. 26 illustrates a dual power dual use semiconductor
thermoelectric generator hybrid with heating and chilling functions
of dual use thermoelectric hybrid 159. The dual power hybrid
chiller device is a combination of thermoelectric generator device
58 of FIGS. 12 and 74 of FIG. 13 wherein both directly combusted
fuel and hot air can be used to produce electricity in single unit
dual use thermoelectric hybrid 159. By adding second controller
board 160 and switch 161 it is possible to operate dual use
thermoelectric hybrid 159 as a thermoelectric generator device or
as a chiller or heater. This feature facilitates electric energy
usage during the day while at night the chiller or heater function
can be used. The chiller function can be use to collect water from
the air. Case 59 houses components of the invention and is
representative of the general form of a box to house components of
the invention. Blower 60 powered by motor 61 forces air into the
box, case 59 circulating around electronic components such as
MOSfet switches 48 and 49, second controller board 160, controller
board 50 and other components including cold fins 21 finally
exiting distinct orifice 63. Legs 64 raise the case 59 to allow air
to efficiently exhaust. Operating Mode-1 is a combustible fuel
device wherein fuel enters venturi style distinct orifice inlet 66
past valve 179 operated by rotary solenoid 178 and is combusted
above burner screen 68 and wherein combusted gas exits distinct
orifice exhaust 162. Rotary solenoid 163 controls valve 164
allowing combustion gases to exit distinct orifice 162. When exit
distinct orifice 162 is in use rotary solenoids 163, 178 and valve
164, 179 are in the open position for Mode-1. In Mode-2, where hot
re-circulated air enters insulated distinctive orifice 165 through
valve 167 operated by rotary solenoid 166 to allow hot air to pass
across the hot fins 29 to exit distinct orifice 168 through valve
170 operated by rotary solenoid 169 allowing the hot air to return
to a thermal store or other close-system recirculating source. In
Mode-3 activating switch 161 activates second controller board 160,
inactivates board 50, and thermoelectric generator device power
functions cease. External electrical power enters electrical plug
171 to second controller board 160 that first rectifies incoming
power into direct current. Second controller board 160 DC-to-DC
switch-converts incoming power into high current low voltage to
drive the secondary coil 46 now operating as a primary coil of the
same upconverter 45. Electrical power from the plug 171 is DC-to-DC
switch-converted down through the E-core 47 to circulate a large
current through ring 40 dragging heat with the current from one set
of fins to the alternate set of fins. MOSfet switch banks 48 and 49
are enabled by second controller board 160 to input switched and
transformed high current DC to flow around ring 40 as to direction.
DC current around 40 may be controlled in one direction or the
other dependant on second controller board 160 for heating or
cooling operating modes. When current flows one direction the hot
fins 29 become cold and cold fin 21 becomes hot. Incoming air
through distinct orifice tube 172 passes through valve 173 that is
activated by rotary solenoid 174. Air or glycol mixture is chilled
by passing over chilled fin 29 to exit distinct orifice tube 175
passing valve 176 actuated by rotary solenoid 177. Plug 69 contains
combined temperate sensor 132 and a resistance-heated igniter 70
that is used in the combustion phase Mode-1 for ignition. All
valves 176, 164, 170, 179 167, and 173 and rotary solenoids 177,
163, 169, 178, 166, and 174 are normally closed until operating
Mode is selected with switch 161. Orifices 63, 65, 165, 172, 168,
162, and 175 are distinct orifices.
[0128] The device described in FIG. 26 can be manufactured to
provide the cooling and heat when power is obtained from the grid.
Thus for versatility in the use of both direct combustion and for
recirculation of hot air from external heat sources a single
thermoelectric generator device comprising the valves to shift
between these different heat sources can be constructed based on
the descriptions in FIGS. 12, 13 and 26.
[0129] Reduced barriers, high efficiency and high purity n-type and
p-type semiconductors play an important role in allowing
high-energy conversion efficiency. Example 1 gives the preferred
range of element percentages by weight for n-type semi-conductor.
Example 2 gives the preferred range and element percentages by
weight for p-type semiconductor. The method of manufacture is
described in detail above with regard to FIG. 1.
Example 1
Reduced Barriers n-Type Semiconductor Composition
TABLE-US-00001 [0130] Element Range Preferred Amount Selenium
5%-12% 10% Bismuth 40%-60% 45% Tellurium remainder to 100% 45%
This n-type selenium-bismuth-telluride-based semiconductor
composition represents a formula [Bi.sub.2Te.sub.3].sub.0.35
[Bi.sub.2Se.sub.3].sub.0.65 approximating a ratio of one part
dibismuth tritelluride and two parts dibismuthtriselenide. This
product appears to be crystalline.
Example 2
Reduced Barriers p-Type Semiconductor Composition
TABLE-US-00002 [0131] Element Range Preferred Amount Antimony
28%-32% 30% Bismuth 8%-12% 10% Tellurium remainder to 100% 60%
[0132] This p-type antimony-bismuth-telluride-based semiconductor
composition represents a formula [Bi.sub.2Te.sub.3].sub.0.35
[Sb.sub.2Te.sub.3].sub.0.65 or about one part dibismuthtritelluride
and 2 parts diantimonytritelluride. Diantimonytritelluride
structural form is a glass. The structure of
dibismuth-tetraantimony-nonatelluride as produced by the method
described herein appears to be crystalline.
[0133] Copper and some other elements greatly degrade performance
of these semiconductors; therefore high purity elements are needed.
Each chemical element should be at least 99.9% pure and preferably
99.999% pure.
[0134] Semiconductors are protected from infiltration of copper
atoms and components of solder by first coating the wafer edges
with a non-conductive high temperature-melting ink, brand named
"mark-tex" high temp 44 manufactured by DYKEM, preferably color
coded products that can reduce the chances of misplacing an n-type
or p-type wafer in a coupon. After the wafer edges are passivated
the wafer is cleaned by dipping it in a solution of one part of 35%
HCl with 2 parts distilled water. After a dip of about 30 seconds
the cleaned wafer is rinsed in deionized water and immediately
placed in a hot nickel plating solution of phosphorus-nickel
material. This plating solution when heated to 95 degrees C.
provides an electroless method of plating. Furthermore, this method
of plating allows co-precipitation of elemental phosphorous on the
wafer sides. Phosphorous content ranges from 1% to 13%. Phosphorous
reduces corrosion on both the hot fins and cold fins. Its hardness
increases after heating. Wafers are removed from the plating
solution after about 30 minutes. This procedure results in a
thickness of nickel on the wafer sides ranging from 15 to 30
microns thick. The wafer edges of the semiconductor do not become
plated because of the anodic oxide produced during anodic slicing
and the non-conductive edge ink coating that protects it. Current
leakage around the wafer edge can be on the order of 400 amps per
wafer if nickel is allowed to plate the wafer edges.
[0135] In a preferred embodiment, after coating the wafer edge with
the high temperature etch resistant material, and plating the wafer
sides with nickel, wafers are then annealed by heating to a
temperature of 250 degrees C. in a hydrogen atmosphere for more
than 2 hours.
[0136] Copper is the metal of choice for hot and cold fins because
of its high electrical and thermal conductivity. To reduce
corrosion and prevent migration of copper into the semiconductors,
fins are coated with metal more resistant to oxidation, preferably
phosphorus nickel. In a preferred embodiment nickel is
electroless-plated on the fins in the same manner and with the same
benefits as plating the wafer sides.
[0137] A simple implementation of the invention uses fins that are
tapered on the end that connect to the n-type and p-type
semiconductors. Either the hot fin or the cold fin or both may be
tapered. The degree of tapering in one or both fins equals that
provided by a single wedge as described in a preferred embodiment.
In lieu of tapered fins it is possible to assemble a ring of
coupons without using a wedge by tapering either or both of the
n-type and p-type wafers.
[0138] To allow the use of parallel wafer sides and uniform
metal-semiconductor filling of the ring hot and cold fins are not
tapered at the end connecting to the semiconductors, instead coated
copper wedges are used uniformly around the ring. Preferably the
copper wedges are coated with nickel and placed in registry with
each coupon as detailed with respect to FIGS. 6, 7 and 8.
[0139] In another preferred embodiment hot fins are arranged
perpendicular to cold fins and hot fins extent towards the center
of the ring. The ends of the hot fins facing the center of the
circle are tapered at the end extending to the center so as to
reduce the likelihood of an electric short caused by fins touching
and at the same time reduce the size of the center opening.
[0140] Electrical energy is extracted from the ring using an
upconverter as described above in texts for FIGS. 6-11. The
critical features of the upconverter are as follows:
[0141] Two cold fins are soldered in the ring to which insulated
multi-layer copper strip laminates have been high-temperature
brazed.
[0142] Brazing of wafers to fins and wedges is accomplished by
diffusion of the pure silver powder addition into the tin-silver
eutectic solder paste allowing wafer-to-fin bonding first by low
temperature eutectic solder means at approximately 270 degrees C.
Later a soldered connection is converted to a brazed connection
that melts well above 340 degrees C. through heating during normal
thermoelectric generator device operation. The conversion of
soldered connections to brazed connections is dependent on the
addition of at least 4% by weight of powdered silver to the
Kester's solder.
[0143] Silver is the metal of choice for upconverter laminates and
connecting cold fins because of its high electrical and thermal
conductivity contributing significantly to thermoelectric generator
device performance by lowering the combined resistance of the ring,
upconverter, and switch bank series circuit.
[0144] Mica or similar heat stable insulating material is placed
between 2 power takeoff cold fins with attached dual laminate
takeoffs. One of these takeoffs is rotated physically 180 degrees
so as to pass current around E-core in the opposite direction
relative to the first.
[0145] The upconverter includes a high frequency E-core transformer
which allows a 40 to 1 voltage increase between input from the ring
and output voltage from the transforming upconverter. It also
includes the use MOSfet switch banks, one for each single turn
loop. The MOSfet switch banks are controlled by make-before-break
controller board. The make-before-break feature is achieved by
using inverted MOSfet drivers. The higher voltage AC is then
rectified to DC after the transformer and then it is again
converted to AC at the standard grid frequency, such 50 and 60
Hertz, in square waveform with pulse width modulation to control
output equivalent RMS voltage. Sine wave output is possible using
the H-bridge driven by a sine wave generator but this method leaves
one third of the energy as heat in the H-bridge switches. Sine wave
outputs require one third more fuel burned in the thermoelectric
generator device or heat passed through the thermoelectric
generator device than required for square wave outputs. Square wave
output is satisfactory for most AC uses.
[0146] An essential feature of this invention is a
make-before-break upconverter circuit. FIG. 24 compares the effect
of inverted MOSfet output to non-inverted outputs. In the
non-inverted output high frequency electromagnetic radiation is
prevalent. This adversely affects other electrical and
communication equipment. As illustrated, by inverting the drive to
MOSfet switch banks current is maintained in the ring and E-core at
all times.
[0147] Non-metallic thermo-stable plastic can be used in lieu of a
metal band with electrical insulator to hold the ring-shaped
thermoelectric generator device in compression.
[0148] Prior to assembly each coupon is tested for its
thermoelectric activity. Voltage for a given temperature
differential is measured separately for each semiconductor in the
coupon and accepted if greater than 200 microvolts per degree C.
for each. Conductivity of the entire coupon is accepted if
resistance is less than 0.000014 Ohms as measured at room
temperature.
[0149] During assembly of the ring silver-modified Kester's lead
free solder paste is applied between each previously tested coupon,
the upconverter power takeoff, and the shortened cold fin placed
180 degrees across from the power takeoff. The addition of at least
4% silver powder to the lead-free eutectic solder paste, that
comprising 3.5% silver and 96.5% tin, allows the eventual
conversion of a solder union to a brazed union. Kester's solder
paste originally melts when heated to 270 degrees C. at a rate of
10 degrees per minute. Upon normal use of the thermoelectric
generator device, the 4% silver powder diffuses into the eutectic
solder changing its melting point to a new value above 340 degrees
centigrade. This original soldered connection becomes a brazed
connection over time. The elevated melting point reduces the
chances of damage to the thermoelectric ring due to its being
operated with too high a temperature differential between the hot
fins and the cold fins.
[0150] After assembly and application of inward compression on the
ring by an insulated metal band, resistance is measured in the ring
and the ring is accepted if resistance is less than 0.001 Ohm. If
higher resistance is found coupons are retested and any high
resistance coupon is removed and replaced with low resistance one.
The above process is repeated as needed until the un-bonded ring
measures 0.001 Ohm. Upon passing the assembled resistance test the
ring is then heated to solder components together. In a preferred
embodiment the rate of heating is 10 degrees per minute to a
temperature of 270 degrees C. After reaching 270 degrees C. the
ring is removed from the heating source and allowed to air cool. In
another preferred embodiment the cold fins are positioned downward
so any excess solder drips along the cold fins creating extra
surface area for heat exchange.
[0151] In another preferred embodiment the completed ring is tested
again for electrical conduction by measuring the resistance of the
ring at room temperature. Resistance of a completed ring should be
less than 0.0014 Ohms. Should the soldered ring measure greater
than 0.001 Ohm this particular ring would be used in the
manufacture of a chiller that can tolerate greater resistance
because of the availability of high externally applied voltage. In
addition a soldered ring with a defective coupon can be used in a
chiller application by conducting current around the defective
coupon.
[0152] The assembled thermoelectric ring is tested by placing a
1,500-Watt electric heater adjacent to the hot fins while blowing
air across the cold fins and measuring the power output from the
secondary of the upconverter attached to a 1,000 Watt load bank.
The expected power output is 1,000-Watts. The final performance
evaluation of the completed thermoelectric generator device is made
by running a completed thermoelectric generator device at 5-kW
electrical output with a flow rate of 1-lb of propane per hour. The
overall efficiency should be greater than 50%.
[0153] In a preferred embodiment heat energy obtained from the sun
using a solar collector is stored in solid particulate material,
preferably porcelain fragments. The preferred solar collector is
flat multi-faceted Fresnel planar mirror array as in FIGS. 15a, 15b
and 15c. The details of construction and operation are discussed
with regard to these FIGs. The size of the Fresnel solar collector
is matched to the needs of the user. In a preferred embodiment heat
is stored in insulated containers having an inlet from the solar
collector at the bottom. Heat is transferred from the solar
collector to a heat store by blowing air through insulated
air-tight lines using a closed system blower. Separate insulated
air lines take hot air from the store and circulate it in a closed
fashion through the thermoelectric generator device. A heat sensor
on the exit line of the thermoelectric generator device controls
the rate of flow of air from storage using a proportional control
valve or by changing blower speeds. A temperature of about 500
degrees C. is preferred exiting the thermoelectric generator
device. A thermoelectric generator device can be operated with air
circulating directly between thermoelectric generator device and
solar collector.
[0154] Energy savings are made when immediate energy needs are
lower than collected solar energy. Excess electrical energy
produced from the conversion of solar energy to electrical energy
in the thermoelectric generator device is stored in the porcelain
fragments using a resistive heater. This process provides a
spinning reserve for the electrical system. The process can also be
used to inject high quality heat into a high quality heat store
from low quality solar heating acquired early morning or late
evening. When the amount of solar energy is lower than needed high
quality heat from a high temperature heat store can be used to make
up the difference. Thus the combination of direct solar energy
utilization together with a high temperature reserve makes use of
much of the solar radiation available. Two-axis solar collector
tracking makes 30% more heat available for storage over that of
single axis tracking.
[0155] Table 3 lists the heat capacity of porcelain. The value
C.sub.p extrapolated to 1025 degrees C. is 1.94 joule/gram/degrees
K
TABLE-US-00003 TABLE 3 Specific Heat Temperature Specific (degrees
C.) Heat 25 0.787 100 0.893 200 0.990 1025 1.94 (extrapolated)
[0156] In a preferred embodiment the heat storage system is
fabricated from insulated, airtight stainless steel barrels with
inlet-outlet distinct orifices so that heat energy containing air
can be circulated through porcelain fragments that fill the
barrels. The volume of each barrel is 7.4 ft.sup.3 and the fill
factor is typically 80%. This fill factor allows air circulation
through out the storage media. Four such heat-storing barrels
contain crushed porcelain fragments with a specific heat between
1.2 and 1.5 J/gK and a density of 2.50. Neglecting the mass of the
barrels the heat storage will be 2,100 kg for a stationary system.
The heat storage capacity for this device is shown in the table 4
below in kW-hours of useful power:
TABLE-US-00004 TABLE 4 Exemplary Storage Capacities Storage Mass Cp
temperature (C.) (kg) (J/g K) kWh 300 2,100 1.03 344 500 2,100 1.2
451 900 2,100 1.5 1,026
The calculation for heat energy stored in 2,100 kg of ceramic
fragments at 900 C. is: Watt-hrs=(1.5 J/g. .degree. K)(1
Watt-sec/J)(1,173K)(2,100 kg)(1,000 g/kg) (1 min/60 sec)(1 hr/60
min)=1,026,375 Watt-hrs, or 1,026-kW-hrs
[0157] An example of operating the energy system for several
Austin, Tex. days in 1990, with a 40 m.sup.2, 20:1 parabolic
collector, using 6 stainless steel barrels similar to those
describe above for heat storage is shown in table 5.
TABLE-US-00005 TABLE 5 Energy Balance Examples July September
December 70% of Solar +114-kWh/day +73.6-kWh/day +32-kWh/day
Radiation Balance from +17 '' +17.3 '' +17 '' day before Daily
Total: +131 '' +91 '' +49 '' System Leakage -2.25-kWh/day
-2.25-kWh/day -2.25-kWh/day Parasitic Load -3.6 '' -3.6 '' -3.6 ''
Electric -36.0 '' -36.0 '' -36.0 '' Generation Heater/Chiller,
-14.4 '' -14.4 '' -14.4 '' 10 ton-hrs Total daily usage -56.25 ''
-56.25 '' -56.25 '' Balance: +75-kWh/day +34.8-kWh/day
-7.25-kWh/day The -7.25-kWh/day represents a daily energy
deficiency.
[0158] The calculations in table 5 show that solar radiation can
supply the average home most months of the year in southern US
climates. There are several ways to cover this deficiency in the
winter months. One is to conserve on electrical usage, 15 hours
instead of 16; the other would be to burn some supplemental fuel.
For instance, the -7.25-kWh/day could be made up by burning 1.5
lbs. of propane each day or 10.5 lbs. each week or 2.3 gal. Another
way is to enlarge the size of the solar collector twenty
percent.
[0159] Other types of solar collector can be employed to
conveniently collect sun energy. Examples include but are not
limited to parabolic dish on a gun mount, parabolic trough with
center focus hot air closed loop pipe, two-axis tracking Fresnel
lens, and two-axis tracking cone collector.
[0160] In another preferred embodiment power conversion efficiency
is improved by circulating chilled water to the cold fins. This can
be accomplished by adding an electrically driven refrigerator to
cool water when excess electricity is available.
[0161] In another preferred embodiment a battery boost allows the
system's micro-controller to shut off the thermoelectric generator
device at night when loading is below a certain load level, only to
restart the thermoelectric generator device when the batteries
drain to a less than minimum preset safe level. The battery system
can be charged with energy from the grid or with electrical energy
from the thermoelectric generator device. By using the utility grid
to charge the battery bank, the utility customer reduces the
likelihood that the utility company will deny service or require
minimum usage.
[0162] In this case should the thermoelectric generator system ever
fail, the utility service can be used as if nothing happened,
bringing in outside energy through the battery system. Thus, energy
from the grid is provided through the battery system to improve the
overall reliability of the system. On the other hand, should the
utility system fail, the thermoelectric generator device can
support a residence or commercial building as if no power failure
had occurred, automatically and without disconnects or switchovers.
Such a hybrid source of electricity provides the user with seven 9s
reliability, up from the standard four 9s reliability realized with
the grid only. To achieve this reliability it is important for the
customer to remain connected to the grid where it is available.
[0163] The above described inventions and implementations
illustrate the broad range of uses of the improved thermoelectric
generator device and its chiller hybrid versions. In addition there
are many other implementations and utilities which can make use of
the valuable properties of these inventions that include
efficiency, low noise and portability.
[0164] In a preferred embodiment a smaller version of the
thermoelectric generator device described in detail herein is made
to be a portable or backpack thermoelectric generator device. By
providing 120-volt AC output the backpack can be used with any tool
or device which would otherwise require proximity to an electric
outlet or portable liquid-fuel stand-alone thermoelectric generator
device.
[0165] In another preferred embodiment a thermoelectric generator
device as illustrated and claimed herein is combined with the motor
portion of a utility such as an electric tool producing a
thermoelectric generator tool. Examples include but are not limited
to a chainsaw, circular saw, reciprocating saw, drill, posthole
digger, and automatic nail driver. The benefit of having a hybrid
tool is to allow the energy demand of the tool to control the fuel
consumption rate by direct feedback.
[0166] In a preferred embodiment the thermoelectric generator
device claimed herein is combined with the motor component of a
compressor with air storage vessel to provide a portable quiet and
efficient air compressor system.
[0167] In another preferred embodiment a small thermoelectric
generator device is fitted to replace batteries in battery powered
utilities such as hand tool, especially those that use a common
battery size and shape to power a variety of different kinds of
tools. In this case the DC output connects directly to an adapter
designed to fit in place of the rechargeable battery.
[0168] In addition to thermoelectric generator tools the
thermoelectric generator device disclosed herein can replace other
means of supplying energy to utilities such as appliances. Thus a
thermoelectric generator device can be combined with a motor driven
compressor used in common household refrigerators and freezers.
Similarly an electric stove can be combined with a thermoelectric
generator device so that the stove is powered by gas or liquid fuel
while the cooking elements and controls are electric. Such
appliances fitted to burn wood would be especially useful in remote
areas where wood is abundant and electricity is not present. As
with thermoelectric generator tools thermoelectric generator
appliances have the benefit of allowing feedback to control the
rate of combustion. In a preferred embodiment appliances combined
with a thermoelectric generator device are designed to provide
electricity through an electrical plug to the electric bus so as to
power other non-hybrid appliances or components.
[0169] In addition to operating thermoelectric generator tools and
appliances the invention can be used to operate electric vehicles
on common fuels but also on solar heated hot air. One pound of
aviation gasoline or jet fuel contains approximately 5.4-kW of heat
energy per pound. To convert this fuel into electricity at an
efficiency of 22%, the conversion would be 1.2-kW per pound. One
pound of hot ceramic fragments, drawn down from 900 degrees C. to
300 degrees C., releases 0.15-kW. One pound of gasoline contains 8
times more energy than a pound of ceramic fragment used as a heat
store. This is misleading, because when the total weight of each
conversion mechanism is considered, the ceramic heat store system
has a power to weight advantage.
[0170] The weigh of a gasoline combustion engine-generator for a
stationary application is 300 to 500 lbs. As a transportation
system the weight of a combustion engine drive-train can weigh 600
lbs. plus 20 gallons of gasoline (120 lbs.) for a total weight of
720 lbs. capable of 400 mi. range. Drive-train weight for a
thermoelectric generator device and motor weigh only 80 lbs. and
with 195 lbs. of ceramic heat store also has a range of 400 miles,
for a total weight of 275 lbs. The combustion engine system weighs
2.6 times more than a heat-store-equipped automobile, both having a
range of 400 miles between refuel and reheat. Examples of various
forms of transportation conveyance are given in Table 6. The
performance listed for "Auto-large" is the actual data derived from
a 95 Lincoln Town Car converted to thermoelectric generator power
using propane as fuel. This chart shows that thermoelectric
generator powered conveyances using only stored solar heat can be
operated to replace hydrocarbon-based fuels at the equivalent of
$2.50 to $3.00 per gallon.
TABLE-US-00006 TABLE 6 Conveyance Performance with Solar Heating
Power Vehicle Heat Store Average Speed Power Range Type kg kWh
Miles/hour kW Miles Auto-small 175 57 70 5 800 Auto-large 352 114
70 20 400 Bus 615 200 30 50 200 Light Rail 1,154 375 40 50 300 Long
Haul Truck 7,039 2,286 70 200 800 100 Unit Train 123,467 40,000 50
4,000 500 Ship & Tow Boat 1,231,671 400,000 10 2000 2000
Airplane-small 1,540 500 200 200 500 Airline Transport 32,845
10,667 300 4,000 800
[0171] Thus having described the method of manufacture of
components, the assembly of components, an efficient means to
extract energy produced by a temperature differential, a means to
improve the overall efficiency of converting heat to electricity by
combining a thermoelectric generator device with a hybrid chiller
and by having given a variety of examples as to how to combine said
thermoelectric generator device with other components to provide a
broad range of useful products, we claim:
* * * * *